The answer appears to be: sRGB, the color space to which gimp defaults (unless you've specified another color space?).
The formula for converting sRGB levels to relative luminance is in the sRGB spec. A table of the Levels and their corresponding relative luminance is here: http://www.chaosreigns.com/hdr/srgb/ This is very close to gamma 2.2 (a logarithm?), varying only slightly for the sake of invertable binary math. -- "I would believe only in a God that knows how to Dance." - Nietzsche http://www.ChaosReigns.com Guns save lives. _______________________________________________ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
